X-Men (Original)

X-Men (Original) - As the Uncanny X-Men were formed, their first mission led them to a direct confrontation with Xavier's old friend, Magnus, now the self-styled "Master of Magnetism" Magneto, who would become their most frequent adversary. The conflict took place in Cape Citadel, a military base Magneto had claimed. This was the first clash of Magneto and Xavier's rivaling ideologies. Although the X-Men acted as super-heroes, growing anti-mutant sentiment eventually marred their reputation.

In their next mission, the X-Men defended Washington, D.C., from the thief and mutant teleporter known as the Vanisher with Duncan's support. They also found that not all mutants were interested in joining their mission when the immovable Blob rejected an invitation to their ranks. Moreover, the X-Men soon had interactions with the super-hero community: clashing with Iron Man, aiding the Sentry against the General, and clashing with the Fantastic Four when Professor X was enslaved by the Puppet Master, among many other adventures.

Magneto eventually returned to plague the X-Men, this time with his own group, the so-called Brotherhood of Evil Mutants, consisting of Quicksilver, the Scarlet Witch, the Toad, and Mastermind. They first confronted the X-Men when trying to take over the nation of Santo Marco, followed by an attempted full-on capture of the X-Men. The X-Men had subsequent disputes with the Brotherhood due to failed attempts by the Brotherhood to recruit Namor, the Sub-Mariner, the Blob, and the thunder god, Thor.